It is not easy to add an intercom to an existing home. Adding wiring within the walls to add an intercom system to an existing home can be very expensive. Analog power line intercom systems have been available for a number of years, for example from Radio Shack, but such devices tend to be quite noisy and therefore difficult to use—especially for the hard of hearing. Such intercom systems are believed to transfer an analog modulated voice signal over an electrical AC line which is received at another point or socket on the electrical line where it is demodulated back into its voice components and amplified. Such systems, as noted, generally fail to provide quality audio.
Power line Audio/Video networks will likely gain wide acceptance and be used extensively in homes in near future. Certain of these networks using the HomePlug® standard were designed to target video streaming. Audio streaming occupies less than 10% of the bandwidth that video streaming uses. Therefore, little consideration has been given to handling audio applications in such video oriented networks.